1. Field of the Invention
The present invention relates to a continuously variable transmission metal belt comprising a metal ring assembly including a plurality of endless metal rings laminated on one another and a plurality of metal elements supported on the metal ring assembly; a process for producing the metal ring; and a process for measuring the shape of the metal ring.
2. Description of the Related Art
Japanese Patent Publication No. 6-6970 discloses a metal ring of a continuously variable transmission metal belt, wherein a portion near a side edge of the metal ring is plastically deformed so that a thickness of the portion gradually decreases in a laterally outward direction of the metal ring. Accordingly, due to bending of the metal belt, a compression stress and a tensile stress on the side edge of the metal ring decrease, which extends the fatigue life of the side edge of the metal ring.
In the conventional metal ring, the fatigue life of the side edge of the metal ring is determined based on a bending stress. However, no consideration of a Hertz stress is taken when determining the fatigue life of the side edge of the metal ring. The Hertz stress, being due to contact between a V-face of a pulley and a neck portion of a metal element, causes the side edge of the metal ring to be a starting point of a fatigue fracture. Therefore, it is difficult to effectively extend the fatigue life of the side edge of the metal ring.